This invention relates to roofing materials and their installation.
In the past, shingles made of asphalt, fiberglass, and the like have been provided in flat packages. Each of these shingles typically measures about 3 feet long and about 1 foot wide and is precut so as to form two parallel slits. Extending about half way across the shingle from one of its longitudinal edges, the slits are disposed about a foot apart and divide the roofing material into three tabs. The remainder of the shingle, also known as the uncut slip, includes a face which is usually coated with a thermally activated adhesive material. Activated when the shingles are exposed to the sun, this adhesive is used to hold the shingles in an overlapping arrangement, with one shingle partially covering the other. The shingles are made so that when they are properly installed, the top shingle covers about one-half the transverse width of the bottom shingle and the slits in contiguous overlapping shingles do not align with each other.
When standard shingles are packaged for sale, they are sold in stacks of about 27 shingles which cover approximately 33.75 square feet. A protective sheet of plastic or waxed paper is placed between contiguous pairs of shingles to keep the adhesive from bonding them together before use. This protective sheet is thrown away as the shingles are being unstacked during placement.
During a roofing job, it is customary for the workmen to carry an unopened stack of shingles up a ladder, open the package on the roof, remove the shingles one at a time, place them in position and then nail or staple them in place. This procedure tends to generate problems. They arise, in part, because the weight of the shingle package, which is about 70 pounds, and its awkward shape makes carrying the shingles up a ladder difficult. Also, a stack of shingles resting on a sloping roof can easily slide off of it. Further, individually placing each shingle is a time-consuming chore.